Industrial cutting or bending machines typically operate by the transfer of energy stored in a rotating flywheel to a drive shaft by which the cutting or bending tool is moved through its operating cycle. The flywheel and shaft are coupled together when a cutting or bending operation is required by the closure of a clutch; when the operation has been completed, the drive shaft is braked to bring the machine back to a condition in which it is ready for another cutting or bending operation. Separate clutch and brake devices can be mounted for example at opposite ends of the drive shaft, or alternatively, a combined clutch and brake unit can be employed. Such combined units can be of compact design so that there is a substantial space saving as compared with separate clutch and brake devices. Moreover, the cost of the combination unit can be significantly less than that for the two separate devices.
It is of course normally desired to operate cutting and bending machines at the highest available production rate, but this places heavy demands on the clutches and brake devices in particular. A specific maximum torque is developed by frictional engagement of frictional material with metal surfaces, urged together by actuators. Considerable heat is necessarily generated in the process and the number of operations per minute that the machine is capable of sustaining can be limited by the amount of heat that can be dissipated.
It is accordingly an object of the invention to provide a combined clutch and brake unit from which heat could readily be dissipated, without substantial prejudice to the compactness and low cost of the unit.